Field of the Invention
Exemplary embodiments of the present invention relate to a light emitting apparatus. More particularly, exemplary embodiments of the present invention relate to a light emitting apparatus that uses a semiconductor light emitting device such as a light emitting diode as a light source.
Discussion of the Background
For a long period of time, cold cathode fluorescent lamps, referred to as “fluorescent lamps,” have been widely used as indoor or outdoor illumination devices in buildings. However, the cold cathode fluorescent lamps have disadvantages such as a short lifespan, poor durability, a limited range of color selection of light and low energy efficiency.
Although light emitting diodes (LEDs) have several advantages such as an excellent responsiveness, high energy efficiency and long lifespan, the usage of light emitting diodes has been confined to limited areas such as backlight sources of a small-sized display device, and the like. However, as high-luminance, high-power white LEDs have been developed, LEDs have recently drawn attention as light sources of light illumination apparatuses.
A typical light emitting apparatus for illumination includes a semiconductor light emitting device such as a light emitting diode, and a substrate such as a printed circuit board. The semiconductor light emitting device may be directly mounted on the printed circuit board, or a package having the semiconductor light emitting device built therein may be mounted on a printed circuit board. When the semiconductor light emitting device is mounted on the substrate or package, a large amount of light is lost in a boundary between the semiconductor light emitting device and the substrate or package. Particularly, in case of a light emitting diode chip using a light-transmissive substrate such as a sapphire substrate as a semiconductor growth substrate or a support substrate, a large amount of light can be used through the light-transmissive substrate. However, the light may be blocked by the printed circuit board or package and the light intensity may be reduced.